The power output of a gas turbine unit can decrease with increasing ambient temperature. This decrease in power can be partially compensated by the use of an evaporative inlet cooling system.
Known totally enclosed water air cooled (TEWAC) turbo generators have a power capability that can decrease with increasing cooling water temperature. If a closed loop cooling water circuit with heat exchange to the ambient air is used, the cooling water temperatures available rise linearly with a rise in ambient temperature. As a consequence, a turbo generator that is correctly sized for gas turbines without evaporative inlet air cooling is often not capable of working with the additional power recovered by evaporative inlet air cooling.
To mitigate this issue one may use a turbo generator with larger size and capability, use pressurization of the turbo generator to increase its capability or add an evaporative spray system to the cooling water heat exchanger. The first is possible for newly built power plants and the second and third need additional equipment which creates additional costs and complexity.